The alphabetical world of crystal structures

Mark Howarth's new protein alphabet takes an unusual slant on the shapes of proteins.

Selected protein crystal structures from the PDB in cartoon format and alphabetical order, overlaid on a diffraction image (provided by E. Lowe), with a central bright-field image of a protein crystal (Click to enlarge)

An interest in the diversity of protein shapes led him to put together a set of protein crystal structures corresponding to the capital letters of the alphabet.

In the paper in Nature Structural and Molecular Biology (1), he explains how he chose the structures, which come from groups around in the world and are freely available via the Protein Data Bank (PDB).

They range from a protein involved in collagen stabilisation, which relates to the role of vitamin C in preventing scurvy, to a toxin from E.coli (2).

Sometimes the letter shape seems to be incidental; sometimes the shape is key to the protein's biological function.

Professor Howarth comments that the set may be useful in illustrating to different audiences the diversity of protein structures attained by natural selection, and that it may also have value in bionanotechnology and synthetic biology.